Earth-moving machine



Mix-ch 13, 1945. J. s. BURNS EARTH MOVING MACHINE Filed Dec. 6, 1943 2Sheets-Sheet 1 March 13, 1945. 4 BURNS 2,371,502

EARTH MOVING MACHINE Filed Dec. -e, 1943 2 Sh'eets-S heet 2 PatentedMar. 13, 1945 g ED STATES.

a invention relates to earth' moving machines with more especial.reference to bulldozers, angledozers, trailbuilders' or bullgraders'inwhich an earthimoving blade is adjustably carried in front .of aself-propelled-vehicle: of crawler or tractor type. l ,1 Hitherto,machines of this character have employed a blade carriage comprisinga-rigid andv massive yoke fulcrumed nearthe rear of the track.subframeand embracing the front of'the tractor, but in my co-pendingapplications Serial Nos. 393,819, 490,822 a blade carriage for. suchmachines is described comprising a parallel linkage extendinglongitudinally outside each trackv subframe, the lower links whereof aretrunnioned .to the track subframes near the rear thereofand a frontcross member carried bysaid linkages, adapted to .adjustthe depth of outwithout, changing the blade rake and camber from that to which it hasbeen set, thus obviating structural and/or operationaldisadvantages ofthe known types of machine Moreover, inthe specific embodimentillustratedin my aforementioned application Serial No. 393,819, thefluid pressure cylinders, by which movementyof the carriage is effected,operate through bellicranks.

or rocking plate fulcrumed on the main frame of thetractor andoperatively connected to the front cross member ofthe blade carriage bydrop arms whereby it is unnecessary to compensate the fluid pressuresystem for oscillations of the track.

In some cases however, it may be considered desirable or necessary forthe fluid pressure cylinders and their bell cranks or rocking platesoperativelyconnected to the front cross member to be fulcrumed on thetrack-subframes instead of on'the main frame, and whenthe tracksoscillate due to the vehicle traversing ground inequalities, thesymmetrical disposition ofthe operating mechanism and linkage isdisturbedwithconsequent movement of the mouldboard and blade fromitsadjusted position or stressing of the links and cylinder, mountingswhich is only partially relieved by the transference of the hydraulicmedium from the cylinder at one side to that attheothen' f The presentinvention has for its object to provide compensating arrangements forsuch subframe mounted operating mechanism effectively to stabilise theblade and minimise stressing of the parts incidental to oscillation ofthe track subframes when traversing surface inequalities. Further andfavourable objects willappear from the following description.

"Inaccordance with the present invention arrangements for compensatingthe effect of track oscillations on the' blade carriage operatingplichanisms of bulldozers and angledozers comprise a swinginglinkage foreach'bell crank or" rocking. plate of the carriage, e'a'ch linkageincluding an oscillating support on the track sub frame onwthefrontzofwhich support the bell crank is fulcrumedand-on the rear ofwhich theloperating,mechanismjfor the bell crank is mounted, and astabilizing link-for said support pivoted on an axisjfixed in-relationto the main frameythe, arrangement being. such that as the subframerocks upwardlythe mounting of the operating mechanism is raised to anextent greater than the bell crank fulcrum so as to substantially retainthe adjustedposition ofthe front end .ofthe bell crankiand thus of theblade.

Preferably the oscillating supports have their axes xfixed in relationto their respective. track subframes and are in the form of triangularplates having a pivot. or fulcrum at each of the threeapices, thefirsticonstituting the axis about which. the support rocks while movingbodily in consonance with the movements of the track subframe, thesecond the joint with the aforementioned co-operating link, and thethird forming afulcrum for the bell cranklever which opera-v tivelyconnects, the piston-rod of the fluid pres-.

sur'ecylinder which is itself mounted on the support to the bladecarriage. vBy this arrangement,

not onlyare the .fulcra of the operating bell cranks moved in consonancewith their respective cylinderv fulcra when the tracks oscillate thus toeffect compensation, but the additional advantage is obtained that thethrust of each fluid pressurecylinder between its own and, its bellcrankcfulcrum .is taken by its rocking support without beingtransmitted'to the other parts of the machine and the necessity forprovidingcomplicatedvalve mechanism .in the fluid system is thusavoided.j i

As will-be:. ,understood, the-triangular 'supporting plates preferredmay be replaced by a triangular assembly of links of appropriatesection.

structural material, and in either case it may be foundconvenient forupwardly projecting bosses on the supports to be fumishedwhich serve astrunnions for the cylinders. 1 l

' The invention will be'further described with reference,-to theaccompanying drawings which illustrate by way of example a specificembodiment fofrcompensating arrangement for an underslungblade carriagesuch as that described in which the compensation is effectedand journals'of the fluid pressure partly in section, the upper half showing in planthe cylinder mounting the rocking plate and top link at the oil-side,and the lower half or sectional plan. view showing the lower. link. 111crumed at the: rear: of; th straclcsubtramea.

The tractor'main frame is designated l and mounts the engine unit 2 anddriver seat 3; while 4 and 5 are respectively the nearside and ofisidecrawler tracks carried by subframes on so-called track frames 6 and].which, when the; tractor is traversing ground inequalities, oscillateabout a track frame pivotifii'n the former? ahorizontal axl borne at therear of the tractor main frame I and which, in the tracton illus:trated, is co-incident with the axis of rotation on the; rear drivingsprockets; 9 of the; crawlert-racksi lil represents: the leaf" springof. the. track sus-- pension extending transversely from. onetrack frameII to the other 7 under theengine unitzt. Ill is the nearside front;idler, It are the sup:- porting wheels and 3thefjockeywheekfm'thecrawler track l', all'. being mountedfionrotationinthe track subframe- 6'. These are standard featunes of thetractorwhich it will. be appreciated are illustrated: purely by way. atexample and: as;- the invention is applicable to other types of:tractor, further detailed descriptioni of thepar ticularconstruction: ofthe tractor: itself is: unnecessarn except im so far as. its partsmount;- thev blade carriage;

Bolted? to: each of" the tracksubframesa It and T ar side platesllfiextendingrf'rom the track frame pivot. 83 forwardlyalong: eachwsublrame, and? welded to: each sideplate I 6. is a bearing bracket. l-L',forming an extension off the trackpivot. 8; upon which bracket orextensions: are mounted outside each track frame a. verticall post, Wfor" thenearside=. track 4, and" I9: for the-offside track: 5-, the.upper ends: of these posts being-welded to. or otherwise secured or:prevented? from. relative movement in relation to, the tractor mainframe- I. In: the particular embodiment i'lius;-- trat'ed? the mountingposts It and; re; are each welded? or bolted tea depending, lip=2lr onafi'ange 2|! projecting.- from the: valance or fender 2-2: overltzingthe rear of. the track, which: valance: is: a. conventional feature and,as will beappreciated; since the upper andzlower attachments of the;mounting posts t8: and t9. remain: fixed; in: relation; to. the.tractor: main frame- 17, they: arenot affected by the relativeoscillation at the track:

frames 62 and. I permitted by the track suspension Hi When.traversingrunevensurfaces;

:llhe: mounting posts: I 8: and i9 each: carry: trun ni'ons: orjournals: 2 55 and} 2E font-he upper and lower'side links: 2? and 28 f"a parallel linkage; the front vertical": links. 29 whereof'areaupstanding portions at the endsof a front crossmember or transom 30. As shownmore clearly in Ei'gt' 2 the transom: 3.0 is: V-ShfirDBii to permitangling or the moul'dboard and; blade which are; con

ventional form and are. designated bythe refer-- encesi3 l and32"respectiive1y', theamoul'dboard hav ing 3:1).1'123 reana centralbearing:braoketfliwhieh takes over: the front-apex offth'e transomSIT-and can be swung; about av hinge pin: 34: sov that. for:bulldozingthe mouldboardands blade are atri'ght; angles to the.longitudinal axis of: the.- tractor: as shown in the upper half oi 2;.while for angledozing the: mouldboamct and blademay: be inclined to:-either side-,, the-:lower;-halfof, Big; 2 showing the blade-settor'angledoaing; to-the nearside. q

} Elachzmounting; nostl8; and. I8 similarly mounts a parallel linkagecomprising an upper side link 21 and a lower side link 28 extendingforwardly from its mounting post along the outside of the tracktor Seethe casemay. he. to the front vertical links. 29 upon which the frontends of the side links are pivoted at 35 and 36 respectively.'onsequently, irrespective of the position of the vertical adjustment ofthe blade as set by the operatingmechanism hereafter described, its rakeand camber remain unaltered throughout the range of adjustment asindicated by the in- I termpted outline A in Fig. 1 and as in theaforementioned: co-pending application Serial No. 393,819, but incontradistinction to the embodiment illustrated in that specification,owing to the lower link 28". being underslung in relation tothe track.subtrame; and the upper-and lower: side l'inks:.being; equidistantlyspacedfrom. the axis of oscillation. of the tracks, i; e;, from: thetrack frame pivot: 6", notwithstanding the fact: that the upper linksare in compression as'herea after explained, the cutting thrust isapplied to thetra-ck subtrame at or below. the axis of oscillationthereby: counteracting or inhibiting any: tendency of the front end ofthe track; to: liftfirom the: ground, and thusensuring stabilityduring'the working: of. the machine. This improved blade: carriage forms: thesubject of my application: Serial No. 490322" and with. such carriage,during normal working or with the; blade raised or lowered thebladethrust exercises: a clockwise moment: as viewed from the nearside (seeFig. 1 about the front pivotal connections 315i of the lower side links28 and transom as 30 sothat the upper side links 21 are in com,-

pression and share such. thrust with the resultant advantage that thelower side links.- are comespondi-ngly relieved: of stress and may be oflighter: section; 4c The side links. 21 andizfl are advantageously ofchannel-section: and at their rearends; havewelded tolthem innerandouter eye-pieces 3:1: and? otstrip; respectively one on. each: side oftheir mounting on. the posts. t'B and I B so: that the crum. pins are imdouble shear:

3B is an. intermediate spacing link: bridging: the side links 21 and 28approximately midway.- of their length forth -purpose of reducing anytendencyof the links? to whip or bend underex CESSiVI8= blade: thrustsuch: as may occur during, working: when the blade strikes, forinstance-fa. treeroot or similar obstruction, and-40 aresta.-. bilizingrollers. carried by the lower links: 28 andri'din-gthe external verticalsurfiaces of cheel'z plates- 4 mounted for the purpose on the tracksuhf-ra-mes near the front thereof so as totake the lateral thrustsapplied to thebl'ade-carryingj structure, more particularly whenangledozing;

At their front ends the sidelinksengage the pivot pins 3 and 36- carriedby the uprights: 28 r at each one? of the transom 30', andprojectingoutwardly from the base, of each upright or ver tidal-link 291s, agui'dechannel 45: for the adjust; ing arms46 which are similar to, thosedescribed in the. aforementioned; (ac-pending application. Serial-393,819; that is to say, their front ends.

ar pinned at. QT. to." brackets, 43 on. the mould board while alongtheir length three holes are provided to be selectively'engagedbylbcking'pins is passing. through apertures; in the. guide. channels4.5;jthe; central. holes. being. used. if the mouldboard; and blade. areto b set. for. bulldozing, as,

in, the upper. half or Fig. 2,, one irontg'and. one.

7 5 rear holeo'f "the respecti ejthrust. arms being.

used if the blade is to be set for angledozing as in the lower half ofFig. 2. I

For adjusting the depth of cut of the blade according to the presentinvention, track frame mounted fluid pressure cylinders 50 and includingmeans compensating the effect of track oscillations are furnished. Asillustrated the fluid pressure cylinder 50 and 5| are trunnioned at 52and 53 on supports 54 and 55 bridging the respective tracks and carriedby the track subframes 6 and 1. The supports 54 and 55 also providefulcrums 56 for bell cranks or rocking plates 58 and 59 which extendforwardly and are connected by drop links 60 to webs 51 on the frontcross member or transom 30. The rams or piston rods 6! and 62 of thefluid pressure cylinder are pivotally connected at 63 and 64 to the bellcranks 58 and 59, the arrangement being.

such as will be understood that when the ra ns 6i and 62 are pushedoutwardly by the fluid pressure the bell cranks 58 and 59 are movedcounterclockwise about their fulcrums 56 to lower the blade carriage,and conversely when.the ramsare moved rearwardly by the fluid pressurethe bell cranks 58 and 59 move in a clockwise direction to lift thelinks 60 and thus raise the blade carriage, the maximum liftedpositionbeing represented by the interrupted outline A in Fig. 1.

In order to compensate for unwanted variation from the set position ofthe blade such as results from oscillation of the tracks when traversinguneven surfaces where .the supports 53 and 54 are rigidly attached tothe track frames 6 and I as conventional, the supports 54 and 55 are,.according to the invention, pivoted at 65 and 66 on the ide-plate I6 oftheir respective subframes which latter also carry inner plates 61providing secondary bearings 68 and 69 respectively coaxial with thebearings 65 and 66.

1G and H are stabilising links for the'respective oscillating supports54 and 55 and have their forward ends pivoted to such supports at 12immediately below the trunnion 52 and 53 while their rear ends havepivots l3 and 14 on the tractor main frame I, and in the embodimentillustrated, carried by brackets and 15 forming a vertical continuationof the mounting ost l8.

In consequence of this arrangement, as will be seen more clearly fromFig. 1, when the near side track 4 encounters aground obstruction whichcauses it to oscillate about its track frame pivot 8 and take up theposition represented by the dot and dash line B, instead of the fluidpressure cylinder 50 being moved bodily rearwardly and thus raising theblade from its adjustedposition, the support 54 being held by itsstabilizing link 60 rocks about its pivot 55 in a counterclockwisedirection resulting in a compensatory movement of the fulcrum 56 for thebell crank 58 so that the blade carriage remains set in its adjustedposition in relation to the tractor main frame I, while asaforementioned the necessity of providing complicated transfer valvemechanism to permit the passage of the hydraulic medium from onecylinder to the other under these conditions is avoided. The lines Al,A2, A3, Bl; B2, B3, and Cl, C2, C3, indicate the corresponding positionsof. the bell crank 58 in the normal, raised and lowered settings of theblade for the neutral and .extreme positions of the track. 4 whentraversing ground inequalitie from which it will be appreciated that themechanism is fully compensating and the blade setting is unaffected bytrack oscillations.

11 indicates the engine-driven pump of the fluid pressure system, 18 thecontainer for oil or other hydraulic medium employed and 19 the controlvalve conveniently placed for manipulation by the operator from the seat3 to raise or lower the mouldboard 3| and blade 32, to hold such bladein any adjusted position, or to leave it free to "fioat or ride over thesurface of the ground.

What I claim is:

1. Apparatus for compensating the effect of track oscillations on theblade carriage operating mechanisms of bulldozers and angledozers havingcrawling tracks wherein the vertical position of the blade is adjustedthrough the medium of bellcranks mounted on the track subframes,comprising a swinging linkage for each bellcrank of the carriage, eachlinkage including an oscillating support on the track subframe on thefront of which support the bell crank is fulcrumed and on the rear ofwhich support the operating mechanism for the said bell crank is mountedand a stabilizing link for saidsupport pivoted on an axis fixed inrelation to the main frame the arrangement being such that as thesubframe rocks upwardly the mounting of the operating mechanism israised to a greater extent than the bell crank fulcrum, so as tosubstantially retain the adjusted position of the front end of the bellcrank and thus of the blade. 7

2. Apparatus according to claim 1 wherein the mechanism is fluidpressure operated and the fluid pressure cylinders are journalled, oneon g each oscillating support, in such manner that as a subframe rocksupwardly the fulcrum of its cylinder is raised to an extent greater thanthe pivot of its oscillating support.

3. Apparatus according to claim 1 wherein the fixed pivots of thestabilizing links are located in the vertical plane of the axis aboutwhich the tracks-oscillate.

4. Apparatus according to claim 1 wherein the blade carriage issuspended from the front ends of the rocking plates by drop links.

5. Apparatus according to claim 1 wherein the blade carriage includes afront cross member mounted on pairs of parallel side links extendinglongitudinally outside the track subframes, and wherein said crossmember is suspended from the front ends of the bellcranks whereby theraising of the blade carriage does not the angular position ofthe blade.

6. Apparatus according to claim 1 including fluid pressure cylinderswherein the supports are furnished with bosses about the pivots of thestabilizing links which erve as trunnions for the journals of the fluidpressure cylinders.

'7. Apparatus according to claim 1 whereineach oscillating supportcomprises an inverted yokeshaped plate the limbs whereof bridge the topof the track and have their lower ends supported by co-axial pivotsborne by member attached to the track subframe.

8. Apparatus according to claim 1 wherein the oscillating supportscomprise V-shaped side plates connected to a channel member the latterproviding bearings for the bell crank and stabilizing link pivots.

affect JOHN STEPHEN BURNS.

